The present invention relates to infrared radiant gas burners or heaters of the type shown and described in U.S. Pat. Nos. 3,785,763; 3,824,064; and 4,035,132.
In this type of burner, the gas-air combustion mixture is blown through a porous refractory board or matrix and caused to burn every efficiency at the outside or burning face of that matrix. The matrix is held on the frame of a burner box by a metal retaining rim extending around the periphery of the outside or burning face of the matrix. The temperature reached at the burning face of such burners are in the order of 1600.degree. F. (870.degree. C.) or more, which means that the metal frame of the burner box and the matrix retaining rim reach comparable temperatures and are subject to severe distortion from such heat. Any distortion or warping of the frame of the burner box in turn affects the plane burning face of the matrix and the seals around the edges of the matrix, with the result that combustion takes place at seal leaks and burns out the burner, or combustion is not even across the face of the burner and the infrared radiation or heating effect is uneven. Whenever any of these events occur, the burner must be replaced.
One of the principal uses of these types of burners at this time is in textile mills where they are used to dry moving webs of fabric as the webs emerge from tanks of liquid dyes, sizings, or the like. The burner matrix is faced vertically, parallel to, and about eight inches away from, the moving fabric web. One of the known advantages of this type of burner is that it heats evenly and, when combustion ceases, cools off rapidly. In textile mill applications of the type described, it can readily be seen that any warping of the burner box frame causing unevenness in the matrix face plane with a resultant unevenness in heating effect cannot be tolerated.